My clinical and laboratory endeavors involve two major areas of immunodermatology. The first deals with studies of patients with various forms of vesiculobullous diseases. We have not only provided detailed clinicoimmunopathological correlations of several heretofore poorly defined diseases, i.e., dermatitis herpetiformis, acquired epidermolysis bullosa and herpes gestationis but we have characterized the antigens to which the antibodies in some of these diseases bind. My second and major area of study is the role of the epidermis as an immunological tissue. We have demonstrated that within normal epidermis Langerhans cells are the only cells which 1) synthesize and express Ia antigens, 2) can present both soluble antigens and haptens to sensitized T cells, 3) are capable of allogenic T cell stimulation in a mixed epidermal-lymphocyte proliferation system, 4) can induce hapten and allogeneic cytotoxic T lymphocytes in vitro, and 5) are of a mesenchymal origin. We have also demonstrated that keratinocytes produce an Interleukin 1-like cytokine which may serve as a second signal in generating T cell responses. Ultraviolet radiation has been shown to modulate many of these functions.